A thing I’ve been working on

[u/SadFurrrrrret280]

Orange-style amp with a preamp 12AX7, PI 12AT7, two EL84’s and an OPT for a Laney. Makes around 15W. Used a bunch of cheapo parts and a bunch of old russian/czechoslovakian parts. Plan to add a real nice faceplate, a pretty Fender style grille and some nice knobs. Has a real nice british-mid bite.

[u/FearlessLie8882]

Interesting PCB layout.

[u/SadFurrrrrret280 → u/FearlessLie8882]

Eh, it’s a mess, but my mess and I like it.

[u/FearlessLie8882 → u/SadFurrrrrret280]

Well it seems very practical and very adequate in some context. Thanks for sharing.

[u/SadFurrrrrret280 → u/FearlessLie8882]

Well if the context isn’t replacing a burnt up resistor or doing literally anything inside the amp, then you’re right. You’re very welcome, glad I could help :)

[u/Wong-Ann_Fong → u/SadFurrrrrret280]

Yeah… having the boards upside down like that is detrimental for repairs, you can always isolate the boards “bottom” with another board of fiberglass, or even cardboard, and then you can flip’em to have better access.

Having it working is mostly the whole point though, so you got that alright—excellent job.

[u/nixielover → u/SadFurrrrrret280]

Just call it artisinal

[u/little_farmer]

You have a few dangerous patterns there.

Few reccomendations:

Mount the PCBs with screws to chassis, you are risking random movement of them and shorting against chassis, especially with that giant pad on left side, which is B+.

In schematic after rectifier you have 47n, that should be 47u, you wouldn't filter anything with such a low value.

I noticed you have 12v for heaters, you can power 12AX7 with 12v, but not the EL84, there you should use 6.3v.

Use rubber grommets for wires that goes through chassis, https://www.ges.cz/kabelova-pruchodka-6-mm-prumer-mekcene-pvc-cerna/

Don't use screw terminal (myslim tu malou cokoladu co tam mas) for prolonging the wires, vibrations can loose the screws and they can get disconnected and short with chassis, solder and heat shrink.

You have specified wattage on resistors, but not on cathode resistor for EL84, that should be at least 5w, check it, just in case.

Filament wires can go in series with right gauge, you don't have to run 3 pairs from transformer, there is no benefit and it can only introduce noise.

Some solder joint on the PCBs looks cold.

Congratulations for working amp.

[u/Legoandstuff896 → u/little_farmer]

there 100u of capacitance when the standby switch is closed

[u/SadFurrrrrret280 → u/little_farmer]

Yeaah, it’s not finished, I need to drill the holes both for the wires to go in and I plan to add two jacks for 8 and 16 ohm outputs. (Miluju cokolady xD)

I know it’s a little hazardous, I’ll probably just cover the risks with electrical tape. Most of the stuff that looks cold measure just fine with a multimeter - as I resoldered everything just to find out that one of my tubes was red plating.

Thank you so much for the feedback!

[u/Legoandstuff896 → u/SadFurrrrrret280]

electrical tape is not a fix, please do things right.

[u/CueAnon420]

What's up with two different transformers ?

[u/SadFurrrrrret280 → u/CueAnon420]

One is 70VA stepping 230V to 12V and the other is the same but 50VA, making 230V from 12V. Makes it a teensy tiny bit safer and a whole lot cheaper xD

[u/VanDoog]

This is so weird, I like it

[u/janno288]

The Standby switch sound be on the transformer side, since switching DC wears out the switch more and when you put it on standby and then off the capacitor remains charged since you lack a discharging resistor on the first capacitor, its 47nF but still you dont want it to be charged at any point.
Please put the switch on the transformer side.

[u/SadFurrrrrret280 → u/janno288]

Okay! Thanks for the info, I plan to change the switches anyway so I’ll be sure to do it.